Device and procedure for collecting a succession of intravenous blood samples

Abstract

A blood sample collection device and procedure which employs a series of pre-evacuated rubber-capped vials for the drawing of successive samples. A hollow cylindrical carrier is used consisting of two cups which are integral base-to-base defining a main chamber and a mid-chamber. A soft rubber disc encloses the mid-chamber and defines an antechamber communicating with an intravenous needle. A piston carrying a double-ended auxiliary needle is slideable endwise in the mid-chamber. The antechamber is enclosed by transparent material such as plastic and is of such size as to admit only a trace of blood through the intravenous needle under venous pressure before the vial is connected, the blood in the antechamber serving as a visual telltale informing the user that the needle is in the lumen of the vein. The main chamber is laterally offset from the mid-chamber and antechamber, enabling the intravenous needle to be inserted at a shallow penetration angle notwithstanding the relatively large diameter of the main chamber and further insuring that the vial cap is penetrated in a random eccentric position. The vial is distinguished by use of an extensive rubber diaphragm held in place by screw-on cap which provides a reliable seal while permitting subsequent opening with only light manual twisting force.

I claim: 
     
       1. In a blood sample collection system for use with an intravenous needle, the combination comprising a pre-evacuated vial having an extensive rubber cap, a carrier in the form of a large cylindrical cup defining a main chamber and a small cylindrical cup defining a mid-chamber, the cups having their mouths facing in opposite directions and being integral with one another base-to-base to form a thin common barrier between them and with their axes parallel and offset from one another to a degree that adjacent portions of the sidewalls thereof are substantially flush, the cups communicating via a clearance opening through the barrier and which is axially aligned with respect to the axis of the small cup, a readily-penetrated soft rubber disc at the mouth of the small cup, an end fitting secured to the mouth of the small cup adjacent the rubber disc for coupling to the intravenous needle and having an axial passageway formed therein, the end fitting being formed of transparent plastic and the axial passageway being relieved to form an antechamber immediately adjacent the rubber disc for reception of a trace of blood under venous pressure as a preliminary visual telltale that the lumen of the vein has been penetrated, a piston fitted for sliding movement endwise in the mid-chamber between limit positions, the piston having an auxiliary double-ended needle axially mounted therein and projecting from the ends thereof one end of which extends through the clearance opening in the common barrier and the other end of which is positioned for penetration of the soft rubber disc, the large cylindrical cup slideably receiving said vial with the rubber cap positioned for penetration by the one end of the auxiliary needle so that when the vial is pressed in, cap-first, the auxiliary needle first penetrates the soft rubber disc to establish communication with the intravenous needle and then penetrates the rubber cap on the vial in a random eccentric position to establish communication between the vial and the intravenous needle for the drawing of a sample of blood into the vial, and with the auxiliary needle being drawn from the rubber disc and then from the cap for resealing of the same when the vial is subsequently removed. 
     
     
       2. The combination as claimed in claim 1 in which the cap is threaded on the vial, the cap having a central rubber diaphragm occupying a substantial portion of the vial diameter thereby insuring insertion of the diaphragm by the auxiliary needle in all eccentric positions of insertion of the vial into the main chamber, the diaphragm having a thickness in all said eccentric positions which is the same and which is only a fraction of the diameter thereof. 
     
     
       3. The combination as claimed in claim 2 in which the cap has an annular internal seat defining an extensive central opening, the diaphragm being retained by the seat to occupy the opening, and a sealing ring interposed between the mouth of the vial and the diaphragm to press the latter against the seat to provide a positive seal when the cap is tightened, the thread being sufficiently shallow as to permit subsequent opening with only light manual twisting force.